<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>下拉菜单</title>
	<style type="text/css">
body,ul,li{ margin:0; padding:0; font-size:13px;}
ul,li{list-style:none;}
#divselect{width:186px; margin:80px auto; position:relative; z-index:10000;}
#divselect cite{width:150px; height:24px;line-height:24px; display:block; color:#807a62; cursor:pointer;font-style:normal;
padding-left:4px; padding-right:30px; border:1px solid #333333; 
background:url(xjt.png) no-repeat right center;}
#divselect ul{width:184px;border:1px solid #333333; background-color:#ffffff; position:absolute; z-index:20000; margin-top:-1px; display:none;}
#divselect ul li{height:24px; line-height:24px;}
#divselect ul li a{display:block; height:24px; color:#333333; text-decoration:none; padding-left:10px; padding-right:10px;}
	</style>
   <script type="text/javascript">
window.onload=function(){
	var box=document.getElementById('divselect'),
	    title=box.getElementsByTagName('cite')[0],
	    menu=box.getElementsByTagName('ul')[0],
	    as=box.getElementsByTagName('a'),
        index=-1;
   
    // 点击三角时
    title.onclick=function(event){
      // 执行脚本
      event=event||window.event;
      if(event.stopPropagation){
          event.stopPropagation();
      }
      else{
          event.cancelBubble=true;
      }
      menu.style.display='block';
    document.onkeyup=function(event){
        event=event|| window.event;
        //按下向下方向键
       for(var i=0;i<as.length;i++){
                as[i].style.background="none"
               }          
	    if(event.keyCode==40){
            index++;
            if(index>=as.length){
                index=0;
                           
                                   }
            as[index].style.background="#ccc"
            }
        
         //按下向上方向键
        if(event.keyCode==38){
            index--;
            if(index<0){
                index=as.length;
            
               } 
            as[index].style.background="#ccc"
            }
                //按下回车键
        if(event.keyCode==13 && index!=-1){
          title.innerHTML=as[index].innerHTML;
          for(var i=0;i<as.length;i++)
          {
            as[i].style.background='none';
          }
          menu.style.display='none';
          index=-1;
        }
       } 
    }
    
      
    
   // 滑过滑过、离开、点击每个选项时
      // 执行脚本
for(var i=0;i<as.length;i++){
as[i].onmouseover=function(){
    this.style.backgournd='#ccc';
}
as[i].onmouseout=function(){
    this.style.background='none';
}
as[i].onclick=function(){
    event=event||window.event;
    if(event.stopPropagation){
          event.stopPropagation();
      }
      else{
          event.cancelBubble=true;
      }
     
      menu.style.display='none';
      title.innerHTML=this.innerHTML
}
}
   // 点击页面空白处时
       // 执行脚本
document.onclick=function(){
    menu.style.display='none';
}      
 }
   </script>
</head>
<body>
	<div id="divselect">
      <cite>请选择分类</cite>
      <ul>
         <li id="li"><a href="javascript:;" selectid="1">ASP开发</a></li>
         <li><a href="javascript:;" selectid="2">.NET开发</a></li>
         <li><a href="javascript:;" selectid="3">PHP开发</a></li>
         <li><a href="javascript:;" selectid="4">Javascript开发</a></li>
         <li><a href="javascript:;" selectid="5">Java特效</a></li>
      </ul>
    </div>
</body>
</html>